“…The lack of such sufficient condition can also be seen from the phase portrait in Figure 3, as the maximum is reached in a region in which d Φ I Φ dt Φ is still strictly positive. Let us indeed recall that the classical Fermat theorem on extremal points (see, e.g., [60] Theorem 5.9) becomes an inequality in the non-local context (see, e.g., [61] Theorem 1 in the fractional case or [62] Proposition 2.2 in the general Caputo-type case), justifying the fact that, after the function reaches a maximum and starts decreasing, the non-local derivative could still be non-negative. Finally, let us observe that the lack of semigroup property can be overtaken by considering a deformation map θ, as shown in Appendix A, that takes in consideration the fact that the system remembers all its history.…”